Question

Calculate the moment of inertia of a hollow cylinder of mass M and radius R about a line parallel to the axis of the cylinder and on the surface of the cylinder.

• A. $M{R}^2$.
• B. $\frac{2}{3}M{R}^2$
• C. $\frac{5}{3}M{R}^2$
• D. None of the above.

Answer 1

The correct option is C $\frac{5}{3}M{R}^2$

The moment of inertia of the cylinder about its axis = $M{R}^2$.
Using parallel axes theorem, $I=I_0+M{R}^2=M{R}^2+M{R}^2=2M{R}^2$.
Similarly, the moment of inertia of a hollow sphere about a tangent is $\frac{2}{3}M{R}^2+M{R}^2=\frac{5}{3}M{R}^2$.